Synergistically active herbicidal mixtures for the control of weeds in rice crops

ABSTRACT

10:1 to 1:3 mixtures of a compound of the formula I   wherein the N-containing ring represents the cyclohexamethyleneimine or the 2-methylpiperidyl radical, with optionally a 2-methylthio-4-ethylamino-6-alkylamino-s-triazine or with a plant growth hormone of the phenoxyacetic acid type possess synergetic effects when used as weed-killer in rice crops.

United States Patent [1 1 Bieringer et al.

[ Mar. 25, 1975 [75] Inventors: Hermann Bieringer, Stein; Ludwig Ebner, Magden, both of Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

22 Filed: Oct. 5, 1972 21 Appl. No.: 295,408

[30] Foreign Application Priority Data Oct. 21, 1971 Switzerland 15338/71 [52] U.S. Cl 71/87, 71/88, 71/93,

[51] Int. Cl A0ln 9/36 [58] Field of Search 71/87, 88, 93

[56] References Cited UNITED STATES PATENTS 3,295,947 1/1967 Kishikawa et a1 71/87 3,393,991 7/1968 Hamm et al. 7l/93 FOREIGN PATENTS OR APPLICATIONS 1,594,916 7/1970 France v.71/87 1,255,946 12/1971 United Kingdom ..7l/87 Primary Examiner-James 0. Thomas, Jr. Attorney, Agent, or FirmI-Iarry Falber; Frederick H. Rabin I [57] ABSTRACT 10:1 to 1:3 mixtures of a compound of the formula I u cNCO-CH -S -P (O-n--C 1:I 2 (I) wherein the N-containing ring represents the cyclohexamethyleneimine or the Z-methylpiperidyl radical, with optionally a 2-methylthio-4-ethy1aminc-6- alkylamino-s-triazine or with a plant growth hormone of the phenoxyacetic acid type possess synergetic effects when used as weed-killer in rice crops.

5 Claims, No Drawings YSTY-NER-GISTICALLY ACTIVE HERBICIDAL vMIXTURES FOR THE CONTROL OF WEEDS IN RICE CROPS N-CO-CH wherein the N-containing ring represents a cyclohexamethyleneimine radical or the 2-methylpiperidyl group, and optionally at least one active substance of formula II S-Cll wherein alkyl denotes a lower alkyl radical containing 2 to 5 carbon atoms, or at least one growth hormone of the phenoxyacetic acid type of formula III O-GH-CO-OR. (1'11 wherein R, represents a chlorine atom or the methyl group, and R represents hydrogen, an alkali atom, or an alkyl radical containing 1 to 8 carbon atoms, preferably l to 4 carbon atoms.

The ratio of the mixture componentslzll or 1:1" is 10-11 to 1:3, preferably 6:1 to 2:] parts by weight.

Suitable alkyl radicals for the formula II are ethyl, npropyl, isopropyl, n-butyl, isobutyl, sec. butyl, tert. butyl and all eight amyl isomers.

As alkyl radicals for the formula III there may be cited preferably methyl, ethyl, n-propyl, isopropyl, nbutyl, isobutyl, hexyl, heptyl and isooctyl.

Particularly important mixture components of type ll are:

2-methylthio-4-ethylamino-o-isopropylamino-striazine, 2-methylthio-4-ethylamino-6-sec.butylamino-striazine, 2-methylthio-4-ethylamino--isobutylamino-striazine, 2-methylthio-4-ethylamino-6-tert.butylamino-striazine, 2-methylthio-4-ethylamino 6-[a,

propylamino1-s-triazine, 2-methylthio-4,6-bis(ethylamino)-s-triazine.

Particularly important mixture components of type lll are:

2,4-dichlorophenoxyacetic acid or the salts thereof,

2,4-dichlorophenoxyacetic acid ethyl ester,

B-dimethyl- 2,4-dichlorophenoxyacetic acid methyl ester,

2,4-dichlorophenoxyacetic acid-n-propyl ester,

2,4-dichlorophenoxyacetic acid isopropyl ester,

2,4-dichlorophenoxyacetic acid-n-butyl ester,

2-methyl-4-chlorophenoxyacetic acid or the salts thereof,

2-methyl-4-chloro-phenoxyacetic acid isobutyl ester,

IZ-methyl-4-chloro-phenoxyacetic acid isooctyl ester,

2-methyl-4-chloro-phenoxyacetic acid ethyl ester.

2-methyl4-chloro-phenoxyacetic ac'id propyl ester 2-methyl-4-chloro-phenoxyacetic acid isopropyl ester,

2-methyl-4-chloro-phenoxyacetic acid butyl ester,

2-methyl-4-chloro-phenoxyacetic acid hexyl ester.

Dithiophosphates of formula I are known from the French Pat. No. 1,594,966 or from the Indian Pat. No. 1 18,938 as herbicides. 1,3,5-Triazines of formula II and phenoxyacetic acid derivatives of formula III have been in use for a long time for the regulation of plant growth, particularly as herbicides.

It was not to be anticipated that dithiophosphates of formula I would develop a synergistic action when used in admixture with active substances of formula ll or formula lll.

By synergism is meant in this connection an increased overall effect which exceeds, in the desired direction, the purely cumulative individual effects of the respective components concerned. In the following text the term is taken to include also the improvement in the sphere ofaction against weeds, the reduction or elimination of undesirable secondary effects of the active substances with respect either to cultivated plants or to the environment in general, and/or the appearance of favourable new properties not inherent in the individual constituents.

The mixtures according to the invention render possible the sustained control of, in particular, the following principal weeds occurring in rice crops:

Limlcrniu pyriduriu Limmocliaris flm'u Bit/0m s'p. Lubclin sp. Boerzllmuviu era-1n Lmlwigia unguslrlfillia Callilriclxe sp. Lmlu'igia pruslrala Cyperus compm'lus Cyperus dlflormis Crperus diffusus Cyperus iria Cyperus microiria C yperus serorinus Digirarl'a mnguilmlis Dupulrium jimceum Ecliinoclzloa colormm Eclzinuclzloa crus-galli Eclipta alba Elaline orienmlis Elarine lriandra Eleoclrarix acicularis EIeoc/mris atropurpureus Eriocaulun cinereum Eriucaulon xiebuldianum Fimbrislylis miliucea Ixophorus zmiselus Leplocliloa chincnsis Lepmcliloa filifnrmis Ludwigia I'L'PLILY Marsilea crenala Marsilea minuru Melampodium sp. Monoclloria \aginalis Nymplzaeu stellata Oenamlre javanica Paspalmn dilalalum Paspalum disricluun Paspalum escrubiculnlum Polygonum spp. Polylrias aniauru Portulaca oleracea Pummugeron spp. Romla imlica Sagilraria pygmaeu Scirpus lalerrflorus Scirpus marilimus Splrenoclea zeylunica Triamliema pormlacasrrum Vundellia 5;].

Such carriers or additives can be either solid or liquid and take theform of solvents, diluents, dispersants, wetting agents, adhesives, thickeners or binders.

The active substance mixtures are formulated accordingly as emulsion or suspension concentrates, wettable powders, dust, scattering powders, or granules.

The sprayable solutions for direct application contain, for example, mineral oil fractions having a high to medium boiling range, particularly a range above 100C, for example diesel oil or kerosene, also coal tar oil or vegetable or animal oils, and also hydrocarbons, for example, alkylated naphthalenes, tetrahydronaphthalene, xylene mixtures, cyclohexanols; and optionally too, moreover, ketones, chlorinated hydrocarbons, such as tetrachloroethane, trichloroethylene or triand tetrachlorobenzenes.

The aqueous application forms used are emulsion concentrates, pastes, or wettable powders, with the addition of water. Suitable emulsifying agents or dispersants are non-ionic products, for example, condensation products of aliphatic alcohols, amines or carboxylic acids containing a long chain hydrocarbon radical of about to 30 carbon atoms and ethylene oxide, for example the condensation product of octadecylalcohol and to moles of ethylene oxide, or that of soya fatty acid and 30 moles of ethylene oxide, or that of industrial oleylamine and 15 moles of ethylene oxide, or that of dodecylmercaptan and 12 moles of ethylene oxide. However, condensation products of ethylene oxide and hydroaromatic polycyclic carboxylic acids or amines may also be used. Among the anionic emulsifying agents that can be used there may be mentioned: the sodium salt of dodecylalcohol sulphuric acid ester, the sodium salt of dodecylbenzenesulphonic aicd, the potassium or triethanolamine salt of oleic acid or abietic acid or of mixtures of these acids, or the sodium salt ofa petroleumsulphonic acid. Suitable cationic dispersants are quaternary ammonium and phosphonium compounds such, for example, as cetylpyridinium chloride or dioxyethylbenzyldodecylammonium chloride.

If the agents according to the invention are used in the form of dusts or scattering agents, they may contain as solid carriers talcum, kaolin, bentonite, sand, calcium carbonate, calcium phosphate, also charcoal, cork powder, sawdust and other substances of vegetable origin.

It is possible to manufacture dusts having a content of 5-10 of the active mixture by diluting a wettable powder with a finely divided solid carrier. Wetting agents and dispersants can also be omitted or replaced by others. The various preparations can contain in conventional manner an admixture of substances that improve the distribution, fixation or penetrability. Examples of such substances are fatty acids, resins, glue, casein or alginates.

The application of granules has proved very advantageous in combating weeds in rice, chiefly in water rice. Such granules are manufactured by dissolving the active substance mixture in an oganic solvent and applying the resulting solution to a granulated mineral, for example attapulgite, SiO granicalcium, bentonite and the like, and then evaporating the solvent.

lt is also possible to use polymer granules. They are prepared by mixing the active substances with polymerisable compounds (urea/formaldehydes, dicyandiamide/ formaldehyde, melamine/formaldehyde or others), whereupon a mild polymerisation is carried out that does not affect the active substances, and the granulation is performed during the gel formation. it is more advantageous to impregnate finished, porous polymer granules (urea/formaldehyde, polyacrylonitrile, polyester or others) which have a specific surface and favourable adsorption/desorption ratio with the active substances, for example in the form of their soutions (in a low boiling solvent) and to remove the solvent.

Polymer granules of this kind can be distributed in the form of microgranules having bulk densities or preferably 300 g/litre to 600 g/litre using atomisers. The dusting can be carried out from aircraft over extensive areas.

Additional fertilisers, surface-active agents or sub stances for increasing the specific weight, such as BaSO can of course be added to the granules.

It is also possible to obtain granules by compacting the carrier with the active substances and additives and then pulverising the product.

The concentration of active substance in herbicidal agents is 0.1- by weight, preferably 5 to 85 by weight.

FORMULATION EXAMPLES Wettable Powder 1-benzyl-2-stearyl- Emulsion Concentrate a. 40 Parts of an active substance mixture are mixed with 10 parts of a mixture of an anionic surface-active compound, preferably the calcium or magnesium salt of monolauryl-benzene-monosulphonic acid, and a non-ionic surface-active compound, preferably a polyethylene glycol ether of monosorbitol-laureate, and the whole is dissolved in xylene. The solution is made up with xylene to a volume of ml to give a clear solution which can be used as spray concentrate and yields a stable emulsion by pouring it into water.

b. Readily soluble active substances can also be formulated as emulsion concentrate according to the following prescription:

20 parts of active substance mixture 70 parts of xylene and 10 parts of a mixture of a reaction product of an alkylphenol and ethylene oxide and calciumdodecylbenzene sulphonate.

are mixed. A sprayable emulsion is obtained by diluting the mixture with water in the desired concentration.

Granules a. 7.5 Grams of an active substance mixture are dissolved in 100 ml of acetone and the resulting acetonic solution is poured on 92 g of granulated attapulgite (mesh size; 24/28 mesh/inch). The whole is well mixed and the solvent evaporated off in a rotary evaporator.

Granules containing 7.5 of active substance. are obtained.

b. To manufacture polymer granules containing of active substance, 1050 to 1 100 g of industrial active substance mixture are dissolved in 2 litres of trichloroethylene and the solution is sprayed in a fluidised bed granulator at 1.5 gauge pressure on to 9230 g of prepared urea/formaldehyde granules. The solvent can be removed by heating the air spirals to about 50C.

c. To manufacture loaded granules containing 7.5 of active substance, 770 g of a solid industrial active substance mixture, 500 g of BaSO 1,000 g of urea and 7,730 g of powdered, porous polyacrylonitrile are moulded in a roll mill and the product subsequently broken up to the desired granular size.

ljerbidical Test 1. Test: 3-4-week oil rice plants (height 12-15 cm) reared in a rice field are transplanted in a test field covered with a layer of water to a depth of 3-5 cm.

a. Postemergent: After 8-12 days the field with its naturally sprouting weeds is treated once with the active substance or active substance mixture under test.

b. At emergent: After 4 days the field is treated once with the active substance or active substance mixture under test while the weeds are sprouting.

IIB 2-methylthio-4-ethylamino-6-tert.butylamin0 s-triazine,

IIIA 2,4-dichclorophenoxyacetic acid isopropyl es ter.

It follows from the result that active substance mixtures accordng to the invention achieve not only an additively improved action against weeds, but that primarily at low concentrations they effect an almost total destruction of weeds that occur naturally in rice cultures, for example Echinochloa, Monochoria, Sagit taria, Eleocharis, Cyperus, Rotala, Lindernia, Vandellia and others. The slight damage caused to the rice culture observed at higher rates of application with pure s-triazine herbicides is, surprisingly, very largely eliminated when these latter are used in admixture with dithiophosphates of the formula I.

Table I Post-emergence Application Preparation Rate of appli- General action Special action Special action Action on cation in on weeds on weeds on weeds rice kg AS/ha 7o (Monochoria) 7r (Sagittaria) Damage in /1 1 2O 60 40 0 IA 2 45 65 45 0 4 50 70 5O 0 8 65 80 65 1.5 1 75 0 2 4O 80 40 0 IB 4 40 85 0 8 99 50 l 0.5 65 0 HA 1 80 85 4 2 85 90 85 4 4 96 4 0.5 65 2 1 75 70 4 11B 2 90 8O 90 15 4 IA+IIA 0.8+O.2 94 0 (4:1) 1.6+O.4 96 96 98 l 3.2+0.8 98 98 98 2 6.4+1.6 99 99 4 IB+IIA 0.8+0.2 90 95 90 0 (4:1) l.6+0.4 96 98 98 l 3.2+O.8 98 99 99 2 6.4+1.6 99 100 99 4 lB+lIB 0.8+0.2 95 95 0 (4:1 1.6+().4 97 99 (l 3.2+O.8 99 99.5 2 6.4+1.6 100 100 3 Table 2 At emergence Application Preparation Rate of application Action on weeds Action in rice in kg AS/ha (Enchinochloa and Monochoria Damage in '71 IA 0,5 60 (J l,() 91) 0 IB ()5 75 (l l.() 90 1) "IA 0,5 80 0 1,0 92 1 lA+lllA (),75+U,5 99 0 LI) +(J,5 100 (J lII+lIlA 75+U 5 99,5 0 If) +0.5 99,5 0

2. Testz'For a special test on important weeds in rice crops, 3-4-week old rice plants grown in a rice field (height of plants 12-15 cm) are transplanted to an experimental field free from emerged weeds and with a water layer ca. 3-5 cm deep, the most important weeds appearing on this field being Echinochloa crus galli and Eleocharis acicularis.

The field, on which has occurred the natural emergence of weeds, is treated once, after 14 days with the active substance or with the active-substance mixture (post-emergent). The mean outside temperature is 30C.

An evaluation of the results is made 4 weeks after application.

The action of the individual compounds with applied amounts of 2.0 and 0.5 kg of A.S./hect., respectively, against weeds is less than that of a 4: 1-A.S.-mixture in which the proportion of the individual components is only 1.6 and 0.4 kg of A.S./hectare, respectively.

3. Test: 3-4-Week old rice plants (height 1215 cm) grown in a rice field were transplanted to a test field having a ca. 3-5 cm deep water layer.

The field was treated after 4 days, before emergence of the naturally occurring weeds. with the active substance, or active substance mixture, in the form of a 7.5% granulate (pre-emergent application).

The results of the evaluation made after 6 weeks, and the crop yield after 17 weeks are given in the table be- The action of the individual compounds with amounts of 1.0 and 0.8 kg of active substance per hect are, respectively, against weeds is less than that of a corresponding l:1-active-substance mixture in which each proportion is only 0.5 kg of active substance per hectare. At the same time, an improvement in crop yield results from the application of the active substance mixture.

What is claimed is:

1. A synergistic herbicidal mixture for the control of weeds in rice crops which comprises in an effective amount an active substance of the formula wherein the N-containing ring represents a cyclohexamethyleneimine radical or the 2-methylpiperidyl group together with an active substance of the formula s-ca N If k (k NH-alkyl wherein alkyl represents a C -C alkyl radical; said active substances being present in a weight ratio of from 10:1 to 1:3.

2. Mixtures according to claim 1, wherein the weight ratio of the active substances is in the range of 6:1 to 1:1.

3. Mixtures according to claim 1, wherein the active substance of formula 11 employed is 2-methylthio-4- ethylamino-6-(a,B-dimethylpropylamino)-s-triazine.

4. Mixtures according to claim 1, wherein the active substance of formula II employed is 2-methylthio-4- ethylamino-6-tert.butylamino-s-triazine.

5. The herbicidal mixture of claim 1, wherein said active substances are 0,0-di-n-propyl-dithiophospborylaceto-Z-methylpiperidide and 2-methythio-4- ethylamino-G-(a, y-dimethylpropyE mino striazine. 

1. A SYNERGISTIC HERBICIDAL MIXTURE FOR THE CONTROL OF WEED IN RICE CROPS WHICH COMPRISES IN AN EFFECTIVE AMOUNT AN ACTIVE SUBSTANCE OF THE FORMULA (-HET-)>N-CO-CH2-S-P(=S)(-O-C3H7)2 WHEREIN THE N-CONTAINING RING REPRESENTS A CYCLOHEXAMETHYLENEIMINE RADICAL OR THE 2-METHYLPIPERIDYL GROUP TOGETHER WITH AN ACTIVE SUBSTANCE OF THE FORMULA 2-(ALKYL-NH-),4-(C2H5-NH-),6-(CH3-S-)-S-TRIAZINE WHEREIN ALKYL REPRESENTS A C2-C5 ALKYL RADICAL, SAID ACTIVE SUBSTANCES BEING PRESENT IN A WEIGHT RATIO OF FROM 10:1 TO 1:3.
 2. Mixtures according to claim 1, wherein the weight ratio of the active substances is in the range of 6:1 to 1:1.
 3. Mixtures according to claim 1, wherein the active substance of formula II employed is 2-methylthio-4-ethylamino-6-( Alpha , Beta -dimethylpropylamino)-s-triazine.
 4. Mixtures according to claim 1, wherein the active substance of formula II employed is 2-methylthio-4-ethylamino-6-tert.butylamino-s-triazine.
 5. The herbicidal mixture of claim 1, wherein said active substances are O,O-di-n-propyl-dithiophosphoryl-aceto-2-methylpiperidide and 2-methythio-4-ethylamino-6-( Alpha , gamma -dimethylpropylamino-s-triazine. 